scholarly journals Probing the mechanism of inhibition of amyloid-β(1–42)–induced neurotoxicity by the chaperonin GroEL

2018 ◽  
Vol 115 (51) ◽  
pp. E11924-E11932 ◽  
Author(s):  
Marielle A. Wälti ◽  
Joseph Steiner ◽  
Fanjie Meng ◽  
Hoi Sung Chung ◽  
John M. Louis ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Single Molecule ◽  
Time Course ◽  
Global Analysis ◽  
Amyloid Β ◽  
Random Coil ◽  
Neuronal Cultures ◽  
Transverse Relaxation Rate ◽  
Rate Profile

The human chaperonin Hsp60 is thought to play a role in the progression of Alzheimer’s disease by mitigating against intracellular β-amyloid stress. Here, we show that the bacterial homolog GroEL (51% sequence identity) reduces the neurotoxic effects of amyloid-β(1–42) (Aβ42) on human neural stem cell-derived neuronal cultures. To understand the mechanism of GroEL-mediated abrogation of neurotoxicity, we studied the interaction of Aβ42 with GroEL using a variety of biophysical techniques. Aβ42 binds to GroEL as a monomer with a lifetime of ∼1 ms, as determined from global analysis of multiple relaxation-based NMR experiments. Dynamic light scattering demonstrates that GroEL dissolves small amounts of high–molecular-weight polydisperse aggregates present in fresh soluble Aβ42 preparations. The residue-specific transverse relaxation rate profile for GroEL-bound Aβ42 reveals the presence of three anchor-binding regions (residues 16–21, 31–34, and 40–41) located within the hydrophobic GroEL-consensus binding sequences. Single-molecule FRET analysis of Aβ42 binding to GroEL results in no significant change in the FRET efficiency of a doubly labeled Aβ42 construct, indicating that Aβ42 samples a random coil ensemble when bound to GroEL. Finally, GroEL substantially slows down the disappearance of NMR visible Aβ42 species and the appearance of Aβ42 protofibrils and fibrils as monitored by electron and atomic force microscopies. The latter observations correlate with the effect of GroEL on the time course of Aβ42-induced neurotoxicity. These data provide a physical basis for understanding how Hsp60 may serve to slow down the progression of Alzheimer’s disease.

scholarly journals Loss of function of the mitochondrial peptidase PITRM1 induces proteotoxic stress and Alzheimer’s disease-like pathology in human cerebral organoids

2020 ◽  
Author(s):  
Dina Ivanyuk ◽  
María José Pérez ◽  
Vasiliki Panagiotakopoulou ◽  
Gabriele Di Napoli ◽  
Dario Brunetti ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Death ◽  
Cortical Neurons ◽  
Amyloid Β ◽  
Neuronal Cell ◽  
Protein Aggregates ◽  
Neuronal Cultures ◽  
Loss Of Function ◽  
Proteotoxic Stress

AbstractMutations in pitrilysin metallopeptidase 1 (PITRM1), a mitochondrial protease involved in mitochondrial precursor processing and degradation, result in a slow-progressive syndrome, characterized by cerebellar ataxia, psychotic episodes and obsessive behavior as well as cognitive decline. To investigate the pathogenetic mechanisms of mitochondrial presequence processing, we employed cortical neurons and cerebral organoids generated from PITRM1 knockout human induced pluripotent stem cells (iPSCs). PITRM1 deficiency strongly induced mitochondrial unfolded protein response (UPRmt) and enhanced mitochondrial clearance in iPSC-derived neurons. Furthermore, we observed increased levels of amyloid precursor protein and amyloid β in PITRM1 knockout neurons. However, neither cell death nor protein aggregates were observed in 2D iPSC-derived cortical neuronal cultures. On the contrary, cerebral organoids generated from PITRM1 knockout iPSCs spontaneously developed over time pathological features of Alzheimer’s disease (AD), including accumulation of protein aggregates, tau pathology, and neuronal cell death. Importantly, we provide evidence for a protective role of UPRmt and mitochondrial clearance against impaired mitochondrial presequence processing and proteotoxic stress. In summary, we propose a novel concept of PITRM1-linked neurological syndrome whereby defects of mitochondrial presequence processing induce an early activation of UPRmt that, in turn, modulates cytosolic quality control pathways. Thus our work supports a mechanistic link between mitochondrial function and common neurodegenerative proteinopathies.

scholarly journals Blood-based high sensitivity measurements of beta-amyloid and phosphorylated tau as biomarkers of Alzheimer’s disease: a focused review on recent advances

2021 ◽  
pp. jnnp-2021-327370
Author(s):  
Joyce R. Chong ◽  
Nicholas J. Ashton ◽  
Thomas K. Karikari ◽  
Tomotaka Tanaka ◽  
Michael Schöll ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Single Molecule ◽  
Emerging Technologies ◽  
Amyloid Β ◽  
High Sensitivity ◽  
Phosphorylated Tau ◽  
Meso Scale Discovery ◽  
Aβ Peptides

Discovery and development of clinically useful biomarkers for Alzheimer’s disease (AD) and related dementias have been the focus of recent research efforts. While cerebrospinal fluid and positron emission tomography or MRI-based neuroimaging markers have made the in vivo detection of AD pathology and its consequences possible, the high cost and invasiveness have limited their widespread use in the clinical setting. On the other hand, advances in potentially more accessible blood-based biomarkers had been impeded by lack of sensitivity in detecting changes in markers of the hallmarks of AD, including amyloid-β (Aβ) peptides and phosphorylated tau (P-tau). More recently, however, emerging technologies with superior sensitivity and specificity for measuring Aβ and P-tau have reported high concordances with AD severity. In this focused review, we describe several emerging technologies, including immunoprecipitation-mass spectrometry (IP-MS), single molecule array and Meso Scale Discovery immunoassay platforms, and appraise the current literature arising from their use to identify plaques, tangles and other AD-associated pathology. While there is potential clinical utility in adopting these technologies, we also highlight the further studies needed to establish Aβ and P-tau as blood-based biomarkers for AD, including validation with existing large sample sets, new independent cohorts from diverse backgrounds as well as population-based longitudinal studies. In conclusion, the availability of sensitive and reliable measurements of Aβ peptides and P-tau species in blood holds promise for the diagnosis, prognosis and outcome assessments in clinical trials for AD.

scholarly journals Plant sphingolipids promote extracellular vesicle release and alleviate amyloid-β pathologies in a mouse model of Alzheimer’s disease

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kohei Yuyama ◽  
Kaori Takahashi ◽  
Seigo Usuki ◽  
Daisuke Mikami ◽  
Hui Sun ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Neuronal Cultures ◽  
Amyloid Β Protein ◽  
Neuronal Marker ◽  
Enhanced Production ◽  
Model Of Alzheimer’S Disease ◽  
Aβ Clearance

AbstractThe accumulation of amyloid-β protein (Aβ) in brain is linked to the early pathogenesis of Alzheimer’s disease (AD). We previously reported that neuron-derived exosomes promote Aβ clearance in the brains of amyloid precursor protein transgenic mice and that exosome production is modulated by ceramide metabolism. Here, we demonstrate that plant ceramides derived from Amorphophallus konjac, as well as animal-derived ceramides, enhanced production of extracellular vesicles (EVs) in neuronal cultures. Oral administration of plant glucosylceramide (GlcCer) to APP overexpressing mice markedly reduced Aβ levels and plaque burdens and improved cognition in a Y-maze learning task. Moreover, there were substantial increases in the neuronal marker NCAM-1, L1CAM, and Aβ in EVs isolated from serum and brain tissues of the GlcCer-treated AD model mice. Our data showing that plant ceramides prevent Aβ accumulation by promoting EVs-dependent Aβ clearance in vitro and in vivo provide evidence for a protective role of plant ceramides in AD. Plant ceramides might thus be used as functional food materials to ameliorate AD pathology.

Ca2+-permeable TRPV1 pain receptor knockout rescues memory deficits and reduces amyloid-β and tau in a mouse model of Alzheimer’s disease

2019 ◽  
Vol 29 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Juyong Kim ◽  
Siyoung Lee ◽  
Jaekyoon Kim ◽  
Sangwoo Ham ◽  
Jung Han Yoon Park ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nervous System ◽  
Mouse Model ◽  
Transient Receptor Potential ◽  
Memory Function ◽  
Amyloid Β ◽  
Neuronal Cultures ◽  
Transient Receptor Potential Vanilloid ◽  
Model Of Alzheimer’S Disease

Abstract The transient receptor potential vanilloid 1 (TRPV1) protein is a pain receptor that elicits a hot sensation when an organism eats the capsaicin of red chili peppers. This calcium (Ca2+)-permeable cation channel is mostly expressed in the peripheral nervous system sensory neurons but also in the central nervous system (e.g. hippocampus and cortex). Preclinical studies found that TRPV1 mediates behaviors associated with anxiety and depression. Loss of TRPV1 functionality increases expression of genes related to synaptic plasticity and neurogenesis. Thus, we hypothesized that TRPV1 deficiency may modulate Alzheimer’s disease (AD). We generated a triple-transgenic AD mouse model (3xTg-AD+/+) with wild-type (TRPV1+/+), hetero (TRPV1+/−) and knockout (TRPV1−/−) TRPV1 to investigate the role of TRPV1 in AD pathogenesis. We analyzed the animals’ memory function, hippocampal Ca2+ levels and amyloid-β (Aβ) and tau pathologies when they were 12 months old. We found that compared with 3xTg-AD−/−/TRPV1+/+ mice, 3xTg-AD+/+/TRPV1+/+ mice had memory impairment and increased levels of hippocampal Ca2+, Aβ and total and phosphorylated tau. However, 3xTg-AD+/+/TRPV1−/− mice had better memory function and lower levels of hippocampal Ca2+, Aβ, tau and p-tau, compared with 3xTg-AD+/+/TRPV1+/+ mice. Examination of 3xTg-AD-derived primary neuronal cultures revealed that the intracellular Ca2+ chelator BAPTA/AM and the TRPV1 antagonist capsazepine decreased the production of Aβ, tau and p-tau. Taken together, these results suggested that TRPV1 deficiency had anti-AD effects and promoted resilience to memory loss. These findings suggest that drugs or food components that modulate TRPV1 could be exploited as therapeutics to prevent or treat AD.

scholarly journals Acoustofluidic Assembly of 3D Neurospheroids to Model Alzheimer’s Disease

2020 ◽  
Author(s):  
Hongwei Cai ◽  
Zheng Ao ◽  
Liya Hu ◽  
Younghye Moon ◽  
Zhuhao Wu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Culture ◽  
Neurodegenerative Diseases ◽  
High Throughput ◽  
Amyloid Β ◽  
Fine Tuning ◽  
Cellular Interaction ◽  
Neuronal Cultures ◽  
Embryonic Mouse

AbstractNeuroinflammation plays a central role in the progression of many neurodegenerative diseases such as Alzheimer’s disease, and challenges remain in modeling the complex pathological or physiological processes. Here, we report an acoustofluidic 3D cell culture device that can rapidly construct 3D neurospheroids and inflammatory microenvironments for modeling microglia-mediated neuroinflammation in Alzheimer’s disease. By incorporating a unique contactless and label-free acoustic assembly, this cell culture platform can assemble dissociated embryonic mouse brain cells into hundreds of uniform 3D neurospheroids with controlled cell numbers, composition (e.g. neurons, astrocytes, and microglia), and environmental components (e.g. amyloid-β aggregates) in hydrogel within minutes. Moreover, this platform can maintain and monitor the interaction among neurons, astrocytes, microglia, and amyloid-β aggregates in real-time for several days to weeks, after the integration of a high-throughput, time-lapse cell imaging approach. We demonstrated that our engineered 3D neurospheroids can represent the amyloid-β neurotoxicity, which is one of the main pathological features of Alzheimer’s disease. Using this method, we also investigated the microglia migratory behaviors and activation in the engineered 3D inflammatory microenvironment at a high throughput manner, which is not easy to achieve in 2D neuronal cultures or animal models. Along with the simple fabrication and setup, the acoustofluidic technology is compatible with conventional Petri dishes and well-plates, supports the fine-tuning of the cellular and environmental components of 3D neurospheroids, and enables the high-throughput cellular interaction investigation. We believe our technology may be widely used as in vitro brain models for modeling neurodegenerative diseases, discovering new drugs, and testing neurotoxicity.

Single-Molecule Imaging of Amyloid-β Protein (Aβ) of Alzheimer’s Disease

2014 ◽  
pp. 47-56
Author(s):  
Marie-Isabel Aguilar ◽  
Xu Hou ◽  
Dusan Losic ◽  
Adam I. Mechler ◽  
Lisandra L. Martin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Single Molecule ◽  
Amyloid Β ◽  
Amyloid Β Protein ◽  
Single Molecule Imaging ◽  
Β Protein

Target Enzyme in Alzheimer’s Disease: Acetylcholinesterase Inhibitors

2019 ◽  
Vol 19 (4) ◽  
pp. 264-275 ◽  
Author(s):  
Mridula Saxena ◽  
Ragini Dubey
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Single Molecule ◽  
Rational Design ◽  
Large Population ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Amyloid Β ◽  
Learning Ability ◽  
Hybrid Molecules

Alzheimer’s Disease (AD), affecting a large population worldwide is characterized by the loss of memory and learning ability in the old population. The enzyme Acetylcholinesterase Enzyme (AChE) is the key enzyme in the hydrolysis of the neurotransmitter acetylcholine and is also the target of most of the clinically used drugs for the treatment of AD but these drugs provide only symptomatic treatment and have the limitation of loss of therapeutic efficacy with time. The development of different strategies targeting the AChE enzyme along with other targets like Butyl Cholinesterase (BChE), amyloid-β (Aβ), β-secretase-1 (BACE), metals antioxidant properties and free radical scavenging capacity has been focused in recent years. Literature search was conducted for the molecules and their rational design which have shown inhibition for AChE and the other abovementioned targets. Several hybrid molecules incorporating the main sub-structures derived from diverse chemotypes like acridine, quinoline, carbamates, and other heterocyclic analogs have shown desired pharmacological activity with a good profile in a single molecule. It is followed by optimization of the activity through structural modifications guided by structure-activity relationship studies. It has led to the discovery of novel molecules 17b, 20, and 23 with desired AChE inhibition along with desirable activity against other abovementioned targets for further pre-clinical studies.

scholarly journals Tumour necrosis factor induces increased production of extracellular amyloid-β- and α-synuclein-containing aggregates by human Alzheimer’s disease neurons

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Daniel R Whiten ◽  
Philip W Brownjohn ◽  
Steven Moore ◽  
Suman De ◽  
Alessio Strano ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Protein Aggregation ◽  
Tumour Necrosis Factor ◽  
Single Molecule ◽  
Tumour Necrosis ◽  
Amyloid Β ◽  
Induced Pluripotent Stem Cell ◽  
Aberrant Protein ◽  
Necrosis Factor

Abstract In addition to increased aberrant protein aggregation, inflammation has been proposed as a key element in the pathogenesis and progression of Alzheimer’s disease. How inflammation interacts with other disease pathways and how protein aggregation increases during disease are not clear. We used single-molecule imaging approaches and membrane permeabilization assays to determine the effect of chronic exposure to tumour necrosis factor, a master proinflammatory cytokine, on protein aggregation in human-induced pluripotent stem cell-derived neurons harbouring monogenic Alzheimer’s disease mutations. We report that exposure of Alzheimer’s disease neurons, but not control neurons, to tumour necrosis factor induces substantial production of extracellular protein aggregates. Aggregates from Alzheimer’s disease neurons are composed of amyloid-β and α-synuclein and induce significant permeabilization of lipid membranes in an assay of pathogenicity. These findings provide support for a causal relationship between two crucial processes in Alzheimer’s disease pathogenesis and suggest that targeting inflammation, particularly tumour necrosis factor, may have beneficial downstream effects on ameliorating aberrant protein aggregation and accumulation.

scholarly journals Using multielectrode arrays to investigate neurodegenerative effects of the amyloid-beta peptide

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Steven Schulte ◽  
Manuela Gries ◽  
Anne Christmann ◽  
Karl-Herbert Schäfer
Keyword(s):  
Alzheimer’S Disease ◽  
Neural Networks ◽  
Alzheimer's Disease ◽  
Neurodegenerative Diseases ◽  
Amyloid Β ◽  
Long Term Potentiation ◽  
Neuronal Cultures ◽  
Amyloid Β Peptide ◽  
Multielectrode Arrays

Abstract Background Multielectrode arrays are widely used to analyze the effects of potentially toxic compounds, as well as to evaluate neuroprotective agents upon the activity of neural networks in short- and long-term cultures. Multielectrode arrays provide a way of non-destructive analysis of spontaneous and evoked neuronal activity, allowing to model neurodegenerative diseases in vitro. Here, we provide an overview on how these devices are currently used in research on the amyloid-β peptide and its role in Alzheimer’s disease, the most common neurodegenerative disorder. Main body: Most of the studies analysed here indicate fast responses of neuronal cultures towards aggregated forms of amyloid-β, leading to increases of spike frequency and impairments of long-term potentiation. This in turn suggests that this peptide might play a crucial role in causing the typical neuronal dysfunction observed in patients with Alzheimer’s disease. Conclusions Although the number of studies using multielectrode arrays to examine the effect of the amyloid-β peptide onto neural cultures or whole compartments is currently limited, they still show how this technique can be used to not only investigate the interneuronal communication in neural networks, but also making it possible to examine the effects onto synaptic currents. This makes multielectrode arrays a powerful tool in future research on neurodegenerative diseases.

scholarly journals Co-aggregation with Apolipoprotein E modulates the function of Amyloid-β in Alzheimer's disease

2021 ◽  
Author(s):  
Zengjie Xia ◽  
Emily Prescott ◽  
Tom Leah ◽  
Helen Dakin ◽  
Eleni Dimou ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Apolipoprotein E ◽  
Cellular Uptake ◽  
Single Molecule ◽  
Late Onset ◽  
Amyloid Β ◽  
Single Molecule Imaging ◽  
Early Stages

Isoforms of Apolipoprotein E (ApoE) determine our risk of developing late-onset Alzheimer's Disease (AD), but the mechanism underlying this link is poorly understood. In particular, the relevance of direct interactions between ApoE and Amyloid-β (Aβ) remains controversial. Here, single-molecule imaging shows that in the early stages of aggregation, all isoforms of ApoE associate with Aβ in large co-aggregates, but then fall away as fibrillation happens. Similar large co-aggregates exist in the brains of AD patients, accounting for around 50% of the mass of aggregated Aβ detected in the frontal cortices of homozygotes with the higher-risk APOE4 gene. The cellular uptake and toxicity of these large co-aggregates are isoform-dependent, suggesting a mechanistic role for ApoE-Aβ interactions in AD.

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